package EveryDay;

import java.lang.reflect.Array;
import java.util.Arrays;

public class P3194 {
    public static void main(String[] args) {
        P3194Test01 p3194Test01=new P3194Test01();
        int[] a={7,8,3,4,15,13,4,1};
        System.out.println(p3194Test01.minimumAverage(a));;
    }
}


class P3194Test01{
    public double minimumAverage(int[] nums) {
        Arrays.sort(nums);
        double minSum=Double.MAX_VALUE;
        for(int i=0,j= nums.length-1;i< nums.length/2;i++){
            double sum= (nums[i]+nums[j])/2.0;
            if(minSum>sum)
                minSum=sum;
            j--;
        }
        return minSum;
    }
}